Ionisation Energy — Structured Questions (Cambridge International A-Level Chemistry): Exam Questions

An isotope of element X has two more protons and two more neutrons than an atom of ⁴¹K.

Deduce the identity of element X.

State the full electronic configuration of each of the following species.

K⁺ ......................................................................

Ti .......................................................................

Co ......................................................................

i) Construct equations to represent the first ionisation energy of potassium and the second ionisation energy of scandium.

first ionisation energy of K .....................................................................

second ionisation energy of Sc .................................................................

ii) State the full electronic configuration of an Sc²⁺ ion.

Table 2.1 shows successive ionisation energies of element Z, which is in Period 3.

Table 2.1

i) Explain why the first ionisation energy generally increases across Period 3.

ii) Deduce the group of the Periodic Table to which element Z belongs. Explain your answer.

Group ................................

Explanation ........................................................................................

State the full electronic configuration of each of the following species.

Mg .......................................................................

Mg²⁺ ...................................................................

Construct an equation to represent the first ionisation energy of magnesium. Include state symbols.

Explain why the second ionisation energy of magnesium is higher than the first ionisation energy.

Complete Table 1.1 to show the composition of the given species.

Table 1.1

Lithium and potassium are Group 1 metals.

State the isotopic symbol and the full electronic configuration for a potassium ion, K⁺, with a nucleon number of 39.

symbol .......................................................................

electronic configuration .............................................................................

Beams of protons, neutrons and electrons behave differently in an electric field due to their differing properties. Fig. 1.1 shows the path of a beam of electrons in an electric field.

On Fig. 1.1, draw and label the paths of a beam of protons and a beam of neutrons in the same field.

Fig. 1.1

Table 1.2 shows the 5th to 8th successive ionisation energies of three elements, X, Y and Z, which are in Period 3 of the Periodic Table.

Table 1.2

i) Deduce the group of the Periodic Table to which element Y belongs. Explain your answer.

Group ...............................

Explanation ..............................

ii) State and explain the general trend in first ionisation energies across Period 3.

iii) Explain why the first ionisation energy of element Y is less than that of element X.

iv) Complete the full electronic configuration of an atom of element Z.

1s² .................

All elements have a value for a first ionisation energy.

i) Define the term first ionisation energy of an element.

ii) Construct an equation to represent the first ionisation energy of aluminium. Include state symbols.

Table 3.1 shows successive ionisation energies of an element A, found in Period 3 of the Periodic Table.

Table 3.1

Use data from Table 3.1 to deduce the identity of element A. Explain your answer.

Fig. 3.1 shows the trend in ionisation energy for Period 3 of the Periodic Table.

Fig. 3.1

i) State and explain the general trend in first ionisation energies across Period 3.

ii) Explain the deviations from the trend shown in Fig. 3.1.

Extract:

The first ionisation energy of an element is:

• The enthalpy / energy needed to remove one mole of electrons from one mole of gaseous atoms
• To form one mole of gaseous 1+ ions / ions with +1 charge

The equation for the first ionisation energy of aluminium is:

• Al (g) → Al^+^ (g) + e^-^

Explain why the second ionisation energy of aluminium is greater than the first ionisation energy.

The first six ionisation energies of an element X are given below in Table 5.1.

Table 5.1

Construct an equation to represent the second ionisation energy of element X. Include state symbols.

Extract:

The first six ionisation energies of an element X are given below in Table 5.1.

Table 5.1

Use the data given above to deduce in which group of the Periodic Table element X is placed. Explain your answer.

The first ionisation energies of the elements in Group 14 are given below in Table 5.2.

Table 5.2

Explain the trend shown by these values in terms of the atomic structure of the elements.

State the full electronic configuration of germanium.

Ionisation energies provide evidence for the electronic structure of atoms.

i) Define the term first ionisation energy.

ii) Construct an equation to represent the second ionisation energy of magnesium. Include state symbols.

iii) Explain the trend in first ionisation energies across Period 3 (sodium to argon). Refer to nuclear charge and shielding in your answer.

Silicon(IV) oxide, SiO₂, and phosphorus(III) chloride, PCl₃, have different structures and physical properties.

i) Describe the structure and bonding of silicon(IV) oxide.

ii) Predict the shape and bond angle of a molecule of phosphorus(III) chloride.

iii) Explain the difference in melting points between silicon(IV) oxide and phosphorus(III) chloride in terms of their structure and bonding.

Ammonia, NH₃, reacts with hydrogen chloride gas to form ammonium chloride, NH₄Cl.

NH₃ + HCl → NH₄Cl

Complete the dot-and-cross diagram to show the bonding in the ammonium ion, NH₄⁺. Show outer electrons only.

Fig. 1.1 shows the elements from the first three periods of the Periodic Table.

Fig. 1.1

Identify an element that fits each of the following descriptions:

i) An element that forms a 2^- ion with the same electronic configuration as Ne

ii) The Period 3 element with the highest boiling point

iii) The element from the first three periods with the largest atomic radius

iv) The element from the first three periods with the highest first ionisation energy

v) The Period 3 element with the successive ionisation energies shown in Table 1.1

Table 1.1

Fig. 1.2 shows the first ionisation energies for six consecutive elements labelled A–F.

Fig. 1.2

Complete the graph to show the first ionisation energies of elements G–K.

Extract:

Fig. 1.2 shows the first ionisation energies for six consecutive elements labelled A–F.

Explain why the value of the first ionisation energy for D is greater than for C.

Successive ionisation energies provide evidence for the arrangement of electrons in atoms. In Table 2.1, the successive ionisation energies of oxygen are given.

Table 2.1

i) Construct an equation to represent the third ionisation energy of oxygen. Include state symbols.

ii) Explain how this data shows evidence of two energy shells in oxygen.

Give the full electronic configuration of the following atoms and ions.

i) Te

ii) Zn²⁺

iii) Cu²⁺

i) Give the electronic configuration for the zirconium 2+ ion, Zr²⁺, starting with [Kr].

ii) Construct an equation to represent the third ionisation energy of zirconium, Zr. Include state symbols.